Presently, the methods and systems available to determine the health and status of certain batteries, such as of the silver-zinc type, are limited. Two parameters to be determined are the battery state of charge (SOC) and its capacity (CAP), usually rated in Amp hours. The current method used to determine the capacity of a silver-zinc battery is to charge it to 100% state of charge, and then fully discharge the battery at constant current. The capacity in Amp hours is determined by multiplying the discharge current (Amperes) by the discharge time (hours). Following this, the battery must be fully charged once again to be ready for use. This method involves a significant amount of charging and discharging. This is extremely time consuming and destructive of the battery health. The latter factor is directly related to the limited cycle life of silver-zinc batteries. Also, no means is currently known to instantaneously measure battery SOC.
Batteries, such as silver-zinc batteries have especially limited cycle lives, and any unnecessary cycling should be avoided. Therefore, a need exists for a method to perform a comprehensive diagnostic on a battery, including determination of SOC and capacity, without performing unnecessary discharge cycling on the battery. Also, a method and apparatus is needed to determine defects in a battery, such as a low electrolyte condition.